Author: Cowie, L.S.
Paper Title Page
MOPFI068 High Repetition Rate Highly Stable S-band Photocathode Gun for the CLARA Project 437
  • B.L. Militsyn, L.S. Cowie, P. Goudket, S.P. Jamison, J.W. McKenzie, K.J. Middleman, R. Valizadeh, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  • M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  Compact Linear Accelerator for Research and Applications (CLARA) is a 250 MeV electron facility which is under development at STFC ASTeC. The CLARA photo-injector is based on a RF photocathode gun operating with metal photocathodes and driven by a third harmonic of Ti: Sapphire laser (266 nm). The injector will be operated with laser pulses with an energy of up to 2 mJ, pulse durations down to 180 fs FWHM and a repetition rate of up to 400 Hz. In order to investigate performance of different photocathodes the gun is equipped with a load-lock system which would allow replacement of the photocathodes. Duration and emittance of electron bunches essentially depends on the mode of operation and vary from 0.1 ps at 20 pC to 5 ps at 200 pC and from 0.2 to 2 mm mrad respectively. Requirements for the stability of beam arrival time at the CLARA experimental area are extremely high and vary from hundreds down to tenths femtoseconds. In the presented article we analyse stability of the guns with 1.5 and 2.5 cell and the beam quality delivered by a gun with coaxial and waveguide coupler and analyse possibility of injection time stabilisation with low level RF and optical feedback system.  
TUPEA058 The Conceptual Design of CLARA, A Novel FEL Test Facility for Ultrashort Pulse Generation 1265
  • J.A. Clarke, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, P.A. Corlett, L.S. Cowie, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.P. Jamison, J.K. Jones, A. Kalinin, B.P.M. Liggins, L. Ma, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, H.L. Owen, R.N.C. Santer, Y.M. Saveliev, R.J. Smith, S.L. Smith, E.W. Snedden, M. Surman, T.T. Thakker, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • R. Appleby, M. Serluca, G.X. Xia
    UMAN, Manchester, United Kingdom
  • R.J. Barlow, A.M. Kolano
    University of Huddersfield, Huddersfield, United Kingdom
  • R. Bartolini, I.P.S. Martin
    Diamond, Oxfordshire, United Kingdom
  • N. Bliss, R.J. Cash, G. Cox, G.P. Diakun, A. Gallagher, D.M.P. Holland, B.G. Martlew, M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • S.T. Boogert
    Royal Holloway, University of London, Surrey, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • L.T. Campbell, B.W.J. MᶜNeil
    USTRAT/SUPA, Glasgow, United Kingdom
  • S. Chattopadhyay
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • D. Newton, A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  The conceptual design of CLARA, a novel FEL test facility focussed on the generation of ultrashort photon pulses with extreme levels of stability and synchronisation is described. The ultimate aim of CLARA is to experimentally demonstrate, for the first time, that sub-coherence length pulse generation with FELs is viable. The results will translate directly to existing and future X-Ray FELs, enabling them to generate attosecond pulses, thereby extending the science capabilities of these intense light sources. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.  
WEPFI064 Prototype Refinement of the VELA Transverse Deflecting Cavity Design 2842
  • P. Goudket, S.R. Buckley, L.S. Cowie, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  The Versatile Linear Accelerator (VELA) at Daresbury Laboratory will deliver low energy (5/6 MeV) short bunches (~40 fs) to a number of industrial experimental stations and for scientific research. In order to measure the longitudinal profile of the bunch an S-band transverse deflecting cavity will be inserted into the beamline. A transverse kick of around 5 MV is required therefore a 9 cell design has been chosen. As part of the design iteration a three-cell prototype has been built. Frequency measurements have been performed on the prototype cavity as well as Coordinate Measuring Machine to confirm that the dimensions are to the required design tolerances. Subsequently, further modelling has been performed to improve and refine the design of the 9-cell cavity, to ensure that the frequency of the final design is within the tuning range of the water thermal control system and that the field flatness requirement can be obtained.